1. Technical Field
The present invention relates to a method and apparatus for analyzing reaction mixtures, and relates more particularly, to a method and apparatus for screening combinatorial libraries.
2. Discussion
Combinatorial chemistry refers generally to methods for rapidly creating collections of compounds having diverse structures and to methods for rapidly testing or screening chemical libraries to discover or optimize compounds or materials exhibiting desired properties.
Combinatorial chemistry is an effective research strategy for discovering useful materials. For example, pharmaceutical scientists have successfully used such techniques to dramatically increase the speed of drug discovery. Material scientists have employed combinatorial methods to develop novel high temperature superconductors, magnetoresistive materials, and phosphors. More recently, scientists have applied combinatorial methods to develop catalysts. See, for example, co-pending U.S. patent application Ser. No. 08/327,513 xe2x80x9cThe Combinatorial Synthesis of Novel Materialsxe2x80x9d (published as WO 96/11878) and co-pending U.S. patent application Ser. No. 08/898,715 xe2x80x9cCombinatorial Synthesis and Analysis of Organometallic Compounds and Catalystsxe2x80x9d (published as WO 98/03521), which are both herein incorporated by reference.
Combinatorial libraries may consist of elements or compounds, e.g., individual library members, that are synthesized or mixed in separate vessels, or arrayed on planar solid supports (wafers) frequently using automated dispensing instruments. Each vessel or wafer array position is provided with a starting reactant, which is treated with different reactants. The treating step can be repeated many times with different sets of reagents resulting in a diverse combinatorial library.
Though when compared to traditional approaches, new and useful materials can be developed in less time using combinatorial methods, further efficiency gains can be achieved by improving library screening. Once a researcher creates a combinatorial library, he or she faces the daunting task of identifying a handful of promising materials out of a combinatorial library comprising hundreds, thousands or perhaps millions of compounds. Generally, the speed at which one may screen libraries for useful properties has not kept pace with the speed at which libraries can be created.
Furthermore, screening library members for catalytic activity presents unique problems. For example, screening methods developed for solid phase catalysts are often unsuitable for use with solution phase catalysts. Furthermore, many screening methods developed for solution-phase catalysts, which rely on quantifying the amount of a desired product formed by contacting reactants with the catalysts, require time consuming separations, because the reactants and catalysts may interfere with detection of the desired product.
The present invention is directed to overcoming, or at least minimizing, one or more of the problems set forth above.
The present invention helps solve many of the problems associated with screening combinatorial libraries. Indeed, the present invention provides methods and devices for parallel or rapid serial screening of libraries made through parallel synthesis. Furthermore, the inventive methods are flexible techniques that can be used to screen both solid phase and solution phase catalysts, and they do not require elaborate procedures for separating reactants, products, and catalysts prior to screening. Although the present invention is especially well suited for screening combinatorial libraries, the inventive method and apparatus can be used to analyze a broad range of chemical transformations.
Thus, in accordance with a first aspect of the present invention, there is provided a method of analyzing reaction mixtures. The method comprises the steps of contacting a fluid sample from one of the reaction mixtures with a sorbent, trapping at least one component of the fluid sample on the sorbent, and detecting the at least one component of the fluid sample trapped on the sorbent. The contacting step, the trapping step, and the detecting step are carried out at least once for each of the reaction mixtures.
In accordance with a second aspect of the present invention, there is provided a method of screening a group of catalysts. The method comprises the steps of combining each of the catalysts with at least one reactant so as to form a plurality of reaction mixtures. The method further comprises contacting a fluid sample from one of the reaction mixtures with a sorbent, trapping at least one component of the fluid sample on the sorbent, and detecting the at least one component of the fluid sample on the sorbent. The contacting step, the trapping step, and the detecting step are carried out at least once for each of the reaction mixtures.
In accordance with a third aspect of the present invention, there is provided an apparatus for analyzing reaction mixtures. The apparatus comprises a reaction block having wells formed along an upper surface, and a sorbent layer disposed above the upper surface of the reaction block such that the wells and the sorbent layer define vessels for containing the reaction mixtures. The sorbent layer is adapted to trap at least one fluid component of the reaction mixtures.
In accordance with a fourth aspect of the present invention, there is provided an apparatus for analyzing reaction mixtures comprising vessels for containing each of the reaction mixtures, and discrete sorbent traps that are in fluid communication with the vessels. The sorbent traps are adapted to trap at least one fluid component of the reaction mixtures.
In accordance with a fifth aspect of the present invention, there is provided an apparatus for screening reaction mixtures in which at least one constituent of the reaction mixtures is contained in depressions located along a top surface of a planar substrate. The apparatus comprises a heating block that is adapted to support the planar substrate and to provide thermal contact with a bottom surface of the planar substrate. The apparatus includes a gas permeable sorbent layer having an upper surface and a lower surface, in which the lower surface of the sorbent layer is disposed above the top surface of the planar substrate. The sorbent layer is adapted to trap at least one vapor phase component of the reaction mixtures. The apparatus further comprise a cover having an upper surface and a lower surface, the lower surface of the reactor cover disposed above the upper surface of the sorbent layer. Passageways are formed in the cover that extend from the lower to the upper surfaces of the cover and provide flow paths for vapor phase components of the reaction mixtures from the upper surface of the cover to the at least one constituent of the reactive mixture.